An axial gas turbine engine, such as an aircraft “jet-engine,” generally comprises an air inlet, a compressor section, a fuel combustion chamber, a turbine section, one or several rotatable drive shafts connecting corresponding compressors and turbines, an exhaust outlet and structures for supporting the drive shafts and for mounting the engine to, e.g., an aircraft.
Typically, the supporting structures are static parts that include an inner shell or ring, for connection to bearings and a centrally located drive shaft, and an outer shell or ring, for connection to, e.g., an engine casing, and where circumferentially distributed elements (struts, vanes) extend between and connect the inner and outer shells and/or rings. An axial gas flow through the engine is allowed to flow between the elements which normally are aerodynamically designed.
Generally, supporting structures need to be capable of transferring radial loads between the drive shaft and the engine casing as well as of withstanding an internal pressure. The particular demands depend on the application and a supporting structure is normally designed with focus on the most important capability. For instance, a supporting structure arranged in the compressor zone is subjected to a high internal pressure and needs normally to have a circular outer shape. Sufficiently massive structures of this type are also capable of transferring radial loads. However, the desire for low-weight products in air-craft applications has generated a need for supporting structures that are less heavy but that still are capable of transferring radial loads as well as of withstanding an internal pressure.